Installation guide
On-Net Dialing Dialing Plan
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ShoreTel 14.2 Planning and Installation Guide 113
User extension - typically 4 digits in length; acts as the number you would dial to reach other users
in your organization
By dividing phone numbers into two parts, the OND feature provides customers with a more seamless
method of migrating from their legacy phone systems to the newer ShoreTel system. OND allows
customers to preserve their existing dialing plans when integrating ShoreTel equipment with their
legacy equipment. While previous releases allowed customers to integrate ShoreTel equipment with
their legacy PBX, the configurations needed to maintain the customer's existing dialing plan were
complex and the complexity increased with the number of people and extensions involved.
For example, if one company acquired another company and the two companies wanted to merge
their phone systems, then no two users could have the same user extension, even if they were at
different sites with different prefixes.
With OND, users can call other users within a site by dialing only the user extension. For inter-site
calls, the users press the numbers of the prefix and the user number. Legacy PBX systems still use off-
system extensions (OSEs) to route inbound calls.
Figure 16: Abbreviated Four-digit Dialing with Extension Prefix
As Figure 16 shows, On-Net Dialing assigns extension prefixes to each site or to a group of sites. All
calls are placed on the network if they are within the same prefix, and the user need only dial the user
extension. Calls preceded with the trunk access code, which is usually 9, are sent to the PSTN.
Benefits of On-Net Dialing
Scalability — For larger organizations, On-Net Dialing enables the creation of a common and
consistent dialing plan that can be replicated throughout an organization that has many offices.
For example, a department store might have a phone in each of its different departments with one
for clothing, furniture, kitchenware, etc. With On-Net Dialing, a user can assign the extensions of
4000, 5000, 6000, and 7000 to each of these departments. By modifying the 3-digit site code/
extension prefix at each location, this approach of assigning 4-digit extensions to departments can